I've just written this, but wonder about the formatting as it results in a continuation of a character's dialogue being on two separate lines. Should the last three lines here all be one paragraph? I took another bite from the end of my sub. 'Anyway, what's at the coast?' 'Nothing in particular. It's just we haven't done it yet.' The waitress arrived with our beers and sat them down on the table. 'I like the coast,' he continued. 'Remember when we were kids... that holiday with your mum and dad?'
The problem isn't that it's a new paragraph. The problem is that I don't automatically know to whom the continuation belongs, either contextually or plainly. It's a new train of thought, so it could belong to either person and the he from he continued isn't enough in the excerpt to clue me in either. If the other person is a she, and I already know this from context prior to this bit, then fine, but if they are both hes, then that he needs to be a name, not a pronoun. ETA: Never mind, never mind. One of the people is I, so that clears it up. But.... You can see how that's a really small clue in just this excerpt. I focused on the part you mentioned, and missed the I. It's fine.
Judgement call. How significant of an interruption is the waitress? If the speakers stop and watch her do her work and wait for her to leave before starting again, I'd go for the separate paragraphs. But if they just sort of talk around her, I'd keep it as one.
I think it's clear. By this point you'll be very familiar with the 'I / he' exchanges, but I just wondered if there was any common rule which says you don't use separate lines a continuation of a speaker's dialogue. It's definitely the latter. I've just tried it as one and it reads better. My only concern initially was that the waitress' introduction felt a bit 'instant' as part of the same paragraph, but maybe not now I read it again.